A mechanism is proposed for the reaction, TiO2+ 2C+ 2Cl2 → TiCl4 + 2CO which accounts for its observed autocatalytic characteristics. A titanium oxychloride species transports the titanium from the titania particle surface to the carbon. Chlorine is not involved in the attack on the titania lattice and the chlorine concentration has but slight effect on the reaction rate. Both titania and carbon geometrical surfaces are involved but internal surface areas play no part in this reaction. Data are presented showing the effect of temperature, TiCl4., Cl2 concentrations and titania and carbon surface areas on the reaction rate. CO2/CO ratios from carbon combustion and titania chlorination are compared.